**Core Concept**
Methanol (methyl alcohol) poisoning is a well-known cause of visual impairment and blindness due to its toxic effects on the optic nerve and retina. The primary mechanism of methanol toxicity involves the metabolism of methanol to its toxic metabolites, formic acid and formaldehyde.

**Why the Correct Answer is Right**
Methanol is metabolized by the enzyme alcohol dehydrogenase to form formaldehyde, which is then converted to formic acid by the enzyme aldehyde dehydrogenase. Formic acid is the primary toxic metabolite responsible for the optic neuropathy and retinal damage seen in methanol poisoning. The formic acid disrupts mitochondrial function in the optic nerve and retina, leading to cellular damage and death.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because methanol toxicity does not primarily affect the cornea.
**Option B:** This option is incorrect because the primary mechanism of methanol toxicity is not through the inhibition of acetylcholinesterase.
**Option C:** This option is incorrect because methanol toxicity is not primarily due to the damage of the ciliary body.

**Clinical Pearl / High-Yield Fact**
Methanol toxicity can be prevented or minimized by prompt treatment with fomepizole, a competitive inhibitor of alcohol dehydrogenase, and supportive care. Early recognition and treatment are critical to prevent long-term visual impairment and blindness.

**Correct Answer:** C. Optic nerve.